StatusBar: barStyle support for Android (API 23+)

Summary:
Android (starting from API 23) supports "light status bar", thus it is possible to extend StatusBar and make `barStyle` property work not only for iOS, but also for Android.

This PR introduces one more `barStyle` option `dark-content` in addition to two existing ones (`default` and `light-content`).
Why there are 3 options instead of 2?

Two simple reasons:
1) to make all existing applications fully compatible with these changes;
2) the default status bar on Android is dark with white text and icons, while on iOS it is light with black text and icons on it. Thus the `default` option means something like "I don't really care, just apply the default color for this platform", while two other options (`light-content` and `dark-content`) allow to accurately specify the required result.
Closes https://github.com/facebook/react-native/pull/10185

Differential Revision: D3952346

fbshipit-source-id: 999a67614abff52321fbeb06298ebf1946c3f1d1

Libraries/Components/StatusBar/StatusBar.js

@@ -24,13 +24,17 @@ const StatusBarManager = require('NativeModules').StatusBarManager;
  */
 export type StatusBarStyle = $Enum<{
   /**
-   * Default status bar style
+   * Default status bar style (dark for iOS, light for Android)
    */
   'default': string,
   /**
-   * Dark background style
+   * Dark background, white texts and icons
    */
   'light-content': string,
+  /**
+   * Light background, dark texts and icons
+   */
+  'dark-content': string,
 }>;
 
 /**
@@ -134,7 +138,7 @@ class StatusBar extends React.Component {
     animated?: boolean,
     backgroundColor?: $FlowFixMe,
     translucent?: boolean,
-    barStyle?: 'default' | 'light-content',
+    barStyle?: 'default' | 'light-content' | 'dark-content',
     networkActivityIndicatorVisible?: boolean,
     showHideTransition?: 'fade' | 'slide',
   };
@@ -191,13 +195,13 @@ class StatusBar extends React.Component {
    * @param animated Animate the style change.
    */
   static setBarStyle(style: StatusBarStyle, animated?: boolean) {
-    if (Platform.OS !== 'ios') {
-      console.warn('`setBarStyle` is only available on iOS');
-      return;
-    }
     animated = animated || false;
     StatusBar._defaultProps.barStyle.value = style;
-    StatusBarManager.setStyle(style, animated);
+    if (Platform.OS === 'ios') {
+      StatusBarManager.setStyle(style, animated);
+    } else if (Platform.OS === 'android') {
+      StatusBarManager.setStyle(style);
+    }
   }
 
   /**
@@ -272,6 +276,7 @@ class StatusBar extends React.Component {
     barStyle: React.PropTypes.oneOf([
       'default',
       'light-content',
+      'dark-content',
     ]),
     /**
      * If the network activity indicator should be visible.
@@ -360,6 +365,9 @@ class StatusBar extends React.Component {
           );
         }
       } else if (Platform.OS === 'android') {
+        if (!oldProps || oldProps.barStyle.value !== mergedProps.barStyle.value) {
+          StatusBarManager.setStyle(mergedProps.barStyle.value);
+        }
         if (!oldProps || oldProps.backgroundColor.value !== mergedProps.backgroundColor.value) {
           StatusBarManager.setColor(
             processColor(mergedProps.backgroundColor.value),

React/Modules/RCTStatusBarManager.m

@@ -18,6 +18,7 @@
 RCT_ENUM_CONVERTER(UIStatusBarStyle, (@{
   @"default": @(UIStatusBarStyleDefault),
   @"light-content": @(UIStatusBarStyleLightContent),
+  @"dark-content": @(UIStatusBarStyleDefault),
 }), UIStatusBarStyleDefault, integerValue);
 
 RCT_ENUM_CONVERTER(UIStatusBarAnimation, (@{

ReactAndroid/src/main/java/com/facebook/react/modules/statusbar/StatusBarModule.java

@@ -170,4 +170,28 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
         }
       });
   }
+
+  @ReactMethod
+  public void setStyle(final String style, final Promise res) {
+    final Activity activity = getCurrentActivity();
+    if (activity == null) {
+      res.reject(ERROR_NO_ACTIVITY, ERROR_NO_ACTIVITY_MESSAGE);
+      return;
+    }
+
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      UiThreadUtil.runOnUiThread(
+        new Runnable() {
+          @TargetApi(Build.VERSION_CODES.M)
+          @Override
+          public void run() {
+            View decorView = activity.getWindow().getDecorView();
+            decorView.setSystemUiVisibility(
+              style.equals("dark-content") ? View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR : 0);
+            res.resolve(null);
+          }
+        }
+      );
+    }
+  }
 }